Experiments and simulation of overturning of an asymmetric rocking block on an oscillating foundation

This paper describes what happens when the base upon which a relatively slender rigid block rests is subjected to a horizontal harmonic acceleration. The force transmitted to the block may be sufficient to initiate rocking or even cause overturning. The number of times the block impacts the base before it overturns (if it does) may vary by a considerable amount. Transient rocking and overturning depend very sensitively on the forcing parameters (amplitude and frequency) and exhibit certain fractal characteristics. Some of the subtle phenomena obtained by numerical simulation are demonstrated by experiments in this investigation. Although the physical experiments described in this paper are relatively simple in terms of geometry, parameter ranges, and modeling assumptions, the emphasis throughout is on qualitative behavior. Despite these limitations, the inherent sensitivity of the dynamics poses some profound questions regarding the concept of experimental repeatability.